Ever heard of radioactive glass? Vaseline glass, which often appears an interesting bright green or yellow color, gets its color from the use of uranium salts-given the glass enough radioactivity to set off a Geiger counter. No, I'm not kidding. Uranium salts come in a natural bright yellow color that ends up shading the rest of the glass into its unique color. Since this yellow color was so unique, it made the glass extremely popular, and still does to this day.

There is no reason to worry if you collect Vaseline glass, however. Geiger counters can pick up even normal background radiation, and this is the amount that Vaseline glass gives off. Not nearly enough to ever be harmful. In fact, the only even theoretical way that Vaseline glass can be harmful is if the glass is cut into a fine powder and inhaled in large amounts in the air.

Vaseline glass is still a beautiful and unique collectible, standing out from normal glass because of its distinctive color. The uranium also gives the glass a very unique aspect: under UV lights the glass will actually glow. This is why many antique dealers use black lights in order to identify true Vaseline glass from similar colored look-alikes.

Most sources say that the first Vaseline glass appeared 1830s. There is some circumstantial evidence that uranium salts may have been used as far back as Roman times, but this claims can't be verified. All Vaseline glass is from modern times, from the 19th century on, and remains a valuable collector's item.

Great Britain produced the far majority of Vaseline/uranium glass, though by the end of World War II, this was no longer the case. A small amount is still produced in the United States and Czechoslovakia, though this is not as valuable as the original British pieces. If you hear or see the term "Uranium Glass," this is the same thing as Vaseline glass, and the two terms are completely interchangeable.

What is remarkable about these pieces is the numerous ways they have been used: for glasses, decanters, candle sticks, and many other items. Vaseline glass shows up in so many interesting forms, which is part of what makes it a wonderful collectible. This type of glass is still considered a valuable antique and is in high demand in many places. As long as the unique yellow color continues to attract people, there will always be a demand.